Early mitral deceleration and left atrial stiffness

Left ventricular (LV) filling deceleration time (DT) is determined by the sum of atrial and ventricular stiffnesses (K(LA) + K(LV)). If K(LA), however, is close to zero, then DT would reflect K(LV) only. The purpose of this study was to quantify K(LA) during DT. In 15 patients, K(LV) was assessed, immediately after cardiopulmonary bypass, from E wave DT as derived from mitral tracings obtained by transesophageal echocardiography and computed according to a validated formula. In each patient, a left atrial (LA) volume curve was also obtained combining mitral and pulmonary vein (PV) cumulative flow plus LA volume measured at end diastole. Time-adjusted LA pressure was measured simultaneously with Doppler data in all patients. K(LA) was then calculated during the ascending limb of the V loop and during DT. LA volume decreased by 7.3 +/- 6.5 ml/m(2) during the first 4/6 of mitral DT, whereas LV volume increased 9.4 +/- 8.4 ml/m(2) ( both P < 0.001). There was a small amount of blood coming from the PV during the same time interval, with the cumulative flow averaging 3.2 +/- 2.4 ml/m(2) (P < 0.001). Mean LA pressure was 10.0 +/- 5.1 mmHg, and it did not change during 4/6 DT [from 7.8 +/- 4.3 to 8.0 +/- 4.3 mmHg, not significant (NS)], making K(LA), which averaged 0.46 +/- 0.39 mmHg/ml during the V loop, close to zero during DT [K(LA(DT)): from - 0.002 +/- 0.08 to - 0.001 +/- 0.031 mmHg/ml, NS]. K(LV), as assessed noninvasively from DT, averaged 0.25 +/- 0.32 mmHg/ml. In conclusion, notwithstanding the significant decrement in LA volume, K(LA) does not change and can be considered not different from zero during DT. Thus K(LA) does not affect the estimation of K(LV) from Doppler parameters.